I stopped by Santa Monica Aquarium today (on Santa Monica between Federal and Colby, north side, in a new mixed use building). The store is less than a month old, so not everything is set up yet. It's a relatively small place completely focused on saltwater fish and corals. There are a number of centerpiece display tanks that will eventually show off corals. The owner is still establishing these tanks.
Reasonable number of fish in stock, all looked healthy. The prices on fish seemed average, though not everything was labeled so it's hard to tell. Not a large drygoods selection yet.
I spoke with the owner for a few minutes. He's knowledgeable and friendly, and seems to be following good husbandry practices.
Should be a worthwhile place in future months!